Brick kilns are designed to finish bricks and produce charcoal or other heat-treated materials. A brick kiln should be constructed to withstand high heat temperatures and have a strong resistance to outdoor elements. There are various designs for brick kilns, the most common types being the beehive model and the slope model.
The beehive models are circular in diameter and covered by a dome roof. A brick kiln designed in the beehive fashion is generally constructed using standard brick. These models are built entirely above the ground, and they contain air inlets around the perimeter at ground level.
Beehive models are fairly easy to construct and require no concrete foundations or complex building materials. A brick kiln designed in this manner is typically durable and may last for several years without requiring any repairs. A fair amount of soil manipulation and landscaping may be required before beginning the construction of beehives kilns.
A slope model brick kiln is similar in shape to a beehive kiln. Slope model kilns have dome shaped covers, but the sides are generally immersed underground so only the roof is exposed. Ignition occurs at the top of the dome, and there is usually only one main air inlet, underground at the center of the kiln.
Slope kilns are usually built between hills or slopes that surround the sides of the kiln. These models also contain several smokestacks to help control ventilation. Due to the usage of excess soil, slope models require fewer bricks for construction, but the smoke stacks require the installation of a steel band in the dome. These bands tend to corrode within a couple of years and will require regular maintenance.
Rich and moist soil is usually a necessary foundation for slope kilns. Clay or sandy soil may cause the kiln to crack and eventually collapse. If the surrounding soil is suitable, construction should be fairly easy.
Both kilns operate using wood-burning fuel. They both perform the same basic functions, heating bricks at extremely high temperatures. Once the bricks are cooked for several hours, they become stronger and more durable. Bricks or other finished materials are then moved to a cooling side of the kiln where they are finished and removed.
A brick kiln can reach dangerously high temperatures and caution should be used when operating or when in the vicinity of the structure. A well-designed kiln can safely last for many years and be relatively low maintenance. Kilns generally require close supervision, however.